A Dy6 complex composed of two Dy3 triangular units, [Dy6(μ3-OH)(CO3)3(bsc)3(MeOH)14(H2O)](Cl)5·(H2O)·(MeOH)2 (1), was isolated and found to exhibit slow relaxation of the magnetisation under zero applied dc field, resulting in a high energetic barrier to relaxation.